It's a 32 bit float device. There is no other format for any of the sampling frequencies. There also seems to be confusion about using a mono only external mic for the rear channels while recording internally on the front channels. From the manual it seems that you can record in stereo with both. Perhaps Zoom can clarify as these are important points when making a buying decision. Reading the manual, this seems to be a six channel recorder, capable of recording two stereo pairs to two separate stereo files, plus a mix. Or it can record front, rear and side to three seperate raw ms tracks, plus a mix. If what I am reading is correct, and also interpreting from the complex mixer diagram in the manual, this capability should be a big part of the marketing of this device.